HAIRS, FEATHERS, AND SCALES. 



15 



is furnished with six or seven large filaments or threads, 

 which appear to have a knob-like hinge in the middle, by 

 which they are bent up on themselves. 



The feathers of Birds are essentially hairs. That 

 shrivelled membrane which we pull out of the interior of a 

 quill when we make a pen, is the medullary portion, dried. 

 There is a beautiful contrivance in the barbs, or beards, of 

 most feathers, which I will illustrate by this feather from 

 the body-plumage of the domestic 

 fowl. Every one must have ob- 

 served the regular arrangement of 

 the vane of a feather, and the ex- 

 quisite manner in which the beards 

 of which it is composed are con- 

 nected together. This is espe- 

 cially observable in the wing-fea- 

 thers — a goose-quill for example, L^. 

 where the vane, though very light j 

 and thin, forms an exceedingly 

 firm resisting medium, the indi- 

 vidual beards maintaining their 

 union with great tenacity, and re- 

 suming it immediately, when they 

 have been violently separated. 



]N~ow this property is of high 

 importance in the economy of the EAEB 0F ™;™ L G FE ^ THEE 

 bird. It is essential that with 



great lightness and buoyancy — for the bird is a flying 

 creature — there be power to strike the air with a broad 

 resisting surface. The wide vanes of the quill-feathers 

 afford these two requisites, strength and lightness ; the 

 latter depending on the material employed, which is very 

 cellular, and the former on the mode in which the indi- 

 vidual barbs, set edgewise to the direction of the stroke, 

 take a firm hold on each other. 



jSTow, in the bodv-feather, which is under the micro- 



